1. Field of the Invention
The present invention relates to a semiconductor device equipped with a fuse for isolating a circuit from the other circuits, and a method of manufacturing the device. And the present invention relates more particularly to a semiconductor device capable of suppressing damages that may be generated at melting of the fuse to a minimum level, and a method of manufacturing the device.
2. Description of the Related Art
In order to remove a defective circuit from a semiconductor device equipped with a redundant circuit, a fuse connected to the defective circuit is melted with, for example, a laser beam. In melting the fuse through irradiation of a laser beam, there occurs sometimes a case in which damages (such as cracks) are generated due to the heat of the laser in an insulating film in the peripheral region of the fuse.
If cracks are developed in the film, infiltration of water, for example, from the outside becomes easy, resulting in a deterioration in the moisture resistance. Because of this, circuits and wirings are formed normally removed from the fuse as much as possible in order to avoid the effect of the cracks on them. More specifically, the circuits and the wirings are formed by, for example, about 100 and 10 .mu.m, respectively, removed from the fuse. However, formation of the circuits and wirings away from the fuse results in an increase in wasteful regions, deteriorating the degree of integration of the circuit.
Techniques for suppressing the propagation of cracks to the periphery of the fuse have been disclosed, for example, in Japanese Patent Application Laid Open No. Sho 57-75442 and Japanese Patent Application Laid Open No. Hei 8-46048.
According to the technique disclosed in Japanese Patent
Application Laid Open No. Sho 57-75442, a polycrystalline silicon protective film connected to a substrate is formed directly below the fuse via an insulating film. By so doing, the heat generated at melting of the fuse is discharged to the outside through the semiconductor substrate to suppress the generation of the cracks.
According to the technique disclosed in Japanese Patent Application Laid Open No. Hei 8-46048, as shown in FIG. 6, after the formation of a fuse 103 in an oxide film 102 on a substrate 101, a dummy film is formed on the oxide film 102. After patterning the dummy film a dummy pattern 104 is formed in the periphery of the fuse 103. In this way, cracks or the like generated at fuse melting is prevented from propagating into the region adjacent to the fuse.
However, the above techniques have the following problems.
In the technique disclosed in Japanese Patent Application Laid Open No. Sho 57-75442, an insulating film is disposed between the fuse and the protective film, so that damages (cracks or the like) may be developed before the heat of laser irradiating the fuse is transmitted to the protective film. This technique has therefore a problem in that it cannot prevent propagation of cracks generated in the insulating film into the regions adjacent to the fuse.
In the technique disclosed in Japanese Patent Application Laid Open No. Hei 8-46048, since the dummy pattern 104 is formed out of one sheet of film, cracks generated at melting of the fuse may propagate into the periphery of the fuse from the upper or lower part of the dummy pattern 104. This technique has an additional problem in that cracks generated in the film of the dummy pattern propagate toward the substrate 101 since the dummy pattern 104 is formed only around the fuse 103.